Why unplugging the treadmill matters

If you're used to running on a treadmill and then go for a run in the great outdoors, one of the first things you might notice is that the real deal feels quite different. Tread runners often describe the difference as running less upright and feeling like the feet are pushing into the ground with more effort. In short, it's more challenging. Those feelings happen to be real. While doing things like changing the elevation grade of the belt will help simulate what it's like to really run, traditional treadmills fall short of activating and conditioning the lower-body muscles the way they are trained during a sprint or a longer-distance jog. That's why some gyms across the country are adding a very creative piece of cardio equipment to their arsenal—a motorless treadmill. The concave designs of "The Curve," made by a company called Woodway, and the TrueForm "Runner," force u...